Paper base phenolic resin laminates are widely used as substrates for printed circuits mounted on electronic devices and so on. However, such paper base phenolic resin laminates or laminates having a composite structure, in which a paper base phenolic resin being a core material is disposed between glass fiber substrates impregnated with an epoxy resin (Patent Literature 3) have had problems in water absorption rate and mechanical strength.
Alternative materials thereof are paper base epoxy resin laminates or laminates having a composite structure, in which a paper base epoxy resin prepreg being a core material is disposed between glass fiber substrates impregnated with an epoxy resin. However, they have been insufficient in electrical properties, particularly, long-term hygroscopicity and electric insulation required for printed-circuit boards (Patent Literatures 1 and 2). Also, when printed-circuit boards are used under high voltage, it is required to prevent a fire due to occurrence of tracking. However, the paper base epoxy resin laminates or the laminates having a composite structure, in which a paper base epoxy resin prepreg being a core material is disposed between glass fiber substrates impregnated with an epoxy resin have problems that the tracking resistance of actual printed-circuit boards is low and there is restriction in circuit design. Hence, phenolic resin laminates having a combination of requirements such as electrical properties, mechanical strength and tracking resistance have been desired.    [Patent Literature 1] Japanese Patent Application Laid-Open (JP-A) No. 61-255850    [Patent Literature 2] JP-A No. 62-56137    [Patent Literature 3] JP-A No. 63-39332